What is a search engine? : Most of us have used the Internet to gather information of some sort. We have used sites like Google, or Yahoo to conduct some form of research, but what are these sites called and how did they come about? The term search engine is technically a general class of programs that search documents for definite keywords on the World Wide Web, as well as USENET newsgroups; and in turn, provides a list of where these documents can be found. The word search engine is usually used to describe sites such as Google, and Yahoo.

How does a search Engine Work? : Step one: a search engine works by sending out a spider to collect as many documents as possible. Step two: a program called an Indexer then reads these documents and creates an index based on the words contained in each document. Ideally, only meaningful results are returned for each query.


Types of search engines: There are three kinds of search/research engines and they are as follows.

General Web Search Engine: defined as a search engine that covers the overall Web, by using its own spider or web crawler to collect Web pages for its own index. General Web Search Engines are designed to search information on the World Wide Web and FTP servers (a standard network protocol used to transfer files from one host to anther host over a TCP-based network such as the Internet). The results are generally presented in a list of results that are often referred to as “search engine results pages” or SERPS. These results may include web pages, images, information and other file types. Unlike web directories, which are maintained only by human editors, search engines maintain real-time information by running an algorithm on a web crawler.

When to use a general web search engine: 1. When searching for a well-defined topic/idea 2. When topic/idea is vague 3. When searching for a specific site 4. When searching the full text of millions of web pages 5.When searching for particular types of documents, sites, file types, languages, geographical location etc.how-this-works-diagram.gif

Examples of useful General Search Engines:
Abbreviations: the world's largest and most comprehensive directory and search engine for acronyms, abbreviations and initialisms on the Internet.
About: helps users find solutions to a wide range of daily needs – from parenting, health care and technology to cooking, travel and many others.
AcroynmFinder: contains more than 1,000,000 human-edited definitions, and is the world’s largest and most comprehensive dictionary of acroynms, abbreviations, and initialisms. Users can search or filter terms in Information Technology, Science & Medicine, Military & Government, Organization & Schools, Business & Finance, as well as Slang & Pop Culture.
AjaxWhois: a comprehensive and easy to use service for finding available domain names and obtaining WHOIS and other information about registered domain names.
Answers: combines the best of community-driven questions and answers with hundreds of respected and trusted editorial reference books, whether it summons the expansive, ever-growing collection of community answers from WikiAnswers, or it taps into its ReferenceAnswers database, a comprehensive set of editorial, licensed reference topics.
Azoos: a search engine that emphasizes quality over quantity.
Behold: a search engine that users can use to find images tagged with specified words.
ChaCha: provides users with free, real-time answers to any question both online and through mobile phones by either texting “ChaCha” (242-242) or using one of our mobile apps. ChaCha has become the leading answers service with more than a billion questions answered to date and is perfect for those in need of fast, free answers while on-the-go.
CompletePlanet: provides users with a comprehensive listing of dynamic searchable databses, with highly relevant documents that cannot be crawled or indexed by surface web search engines.
Definitions: an online multilingual dictionary that provides instant lookup and translations of word and phrase definitions, complete with images.
FaganFinder: an excellent collection of Internet tools, mostly for helping the user find anything and everything online. Users can begin their search using the home page as a starting point, or use one of the focused pages such as image search, academic/reference, and shopping.
FindSounds: a free site for finding sound effects on the Web. It is similar to Google and Yahoo search engines, with a focus on sounds.
Google: possibly the most popular web search. Provides users with easy access to billions of web pages, and has many special features to help the user find exactly what they are looking for.
Healia: a premier and trusted search engine for health information and personal support. Healia provides users with a health search engine, an online health community, health news and tips, and consumer-friendly health information guides to help people access high quality and personalized health information.
KidsClick!: a search engine designed for kids by librarians, that offers kid friendly results.
Lyrics: excellent search engine for finding song lyrics.
MunduSearch: Helsps users find pages & documents, sounds, lyrics and videos. For music videos, users need only enter some words from a song they have heard.
OmniMedicalSearch: an excellent search engine for medical information, it was ranked as top 5 medical search engine by About.com.
Scirus: the most comprehensive scientific research tool on the web. With over 440 million scientific items indexed at last count, it allows researchers to search for not only journal content but also scientists' homepages, courseware, pre-print server material, patents and institutional repository and website information.
SlideFinder: helps users find PowerPoint presentations.
StillTasty: a useful food date/edibility search engine.
Technorati: a blog search engine.
Yahoo: one of the most popular search engines.
YouTube: an excellent video search engine.



Meta Search Engine: defined as a search engine that searches multiple search engines like Google, Yahoo or Bing! etc from a single search page, usually removing duplicate results. Meta Search Engines use 256px-Meta-search-en.svg.png most popular, well indexed, and comprehensive sources for their results. The results are usually highly relevant as meta search engines normally grab the first items from the relevancy-ranked list of results that are returned by the individual search engines. One cannot do a complex search, such as field search by using a meta search engine.

When to use a meta search engine: 1. When a user wants to retrieve a reasonably small number of relevant results 2. When the topic is vague 3. When the user wants the convenience of searching a variety of different content sources from one search page.

Examples of Meta Search Engines:
Browsys: a search engine that users can search and gather results from multiple search services at once, using a convenient and intuitive interface.
Yippy: provides users with a private, protected web browsing and search experience.
Dogpile: provides users with all the best results from leading search engines including Google, Yahoo! and Bing, so you find what you’re looking for faster.
HotBot: a useful search engine that searches the web as well as classifieds, job postings, weather forecasts, and shopping deals.
Info.com: Meta-Search allows users to search multiple leading search engines at once, returning more comprehensive and relevant results fast.
Ixquick: is an excellent metasearch engine.
Kayak: Helps the user find and book cheap flights, hotels, vacations and rental cars.
Mamma: is known as the mother of all meta search engines.
MetaCrawler: is a meta search engine that provides the user with images, audio, video, news from Google, Yahoo!, Bing, and many more search engines.
PolyMeta: is an intelligent metasearch and clustering engine.



Topical or Vertical Search Engines: simply put, topical or vertical search engines are search engines that are focused on a specific industry, sector or topic. This type of search engine is used when the user fails to find or has difficulty finding the specified content in a general search engine or meta search engine. For this reason, the topic of vertical search is closely related to that of the deep Web
user-guide-lexis-nexis-01.jpg
Example of a Topical or Vertical Search Engine

How do Topical/Vertical Search Engines work?
Step one: user enters keywords related to a specific topic in the “Enter Search Terms” box, and group them together using “connectors” such as
  • The word “and”- this links search concepts
  • The word “or”- this links synonyms and related terms
  • An exclamation mark “!” retrieves variable forms of the search terms, this will retrieve articles that contain the words entered into the “enter search terms” box.
Step two: user must select sources. Each search interface defaults to a specific source grouping. The user will then click on the source drop down menu to examine the available groupings. The user will scroll through the list and select the one that is most appropriate to your research needs.
Step three: The final step is to limit or expand the dates if necessary and then click the search button.
The results will be listed in order of relevance, but they can also be viewed by publication date or publication type. In order to view the article, the user must click on its title, the full text of the article with the specified search terms will be highlighted in red within the text of the article.

Examples of Topical/Vertical Search Engines:
AcademicInfo: AcademicInfo is an online education resource center for online degrees, online courses and distance learning information from a selection of online accredited schools
Awesome Library: Organizes the Web with 37,000 carefully reviewed resources, including the top 5 percent in education.
Britannica: a leading provider of learning and knowledge products. One of the world's most trusted sources of information on every topic imaginable - from the origins of the universe to current events and everything in between.
Education World: a resource for educators that provides original content, including lesson plans, practical information for educators, information on how to integrate technology in the classroom, web site reviews, employee listings and more.
InfoMine: a virtual library of Internet resources relevant to faculty, students, and research staff at the university level. It contains useful Internet resources such as databases, electronic journals, electronic books, bulletin boards, mailing lists, online library card catalogs, articles, directories of researchers, and many other types of information.
ArtNet: place to buy, sell and research fine art online.
Canada One: Canadian businesses and business resources
YellowPages: one of the most popular topical/vertical search engines for searching businesses.
WhitePages: one of the most popular topical/vertical search engines for a people search.
World Executive: users can research and reserve cheapflights and the besthotels - from motels to the very best 5 star hotels, across thousands of destinations in Europe, the USA and around the globe.
Health Index: network of physicians and researchers whose goal is to help promote world health by providing extensive information on prevention, wellness, and therapy to the world community.
TurboScout: an excellent multi-search engine site.



Advantages & Disadvantages of search/research engines:

There are many advantages and disadvantages when it comes to using search engines, below are a few examples.
Advantages:
  • The indexes of search engines are normally incalculable, and represent substantial portions of the Internet which offer a wide variety and quantity of information resources
  • Search engine software is becoming more and more sophisticated, this allows users to precisely describe the information that they are seeking
  • Search engines help to organize the Internet and individual websites into an organized list that can be used more easily, as a large amount of information can sometimes be scattered in various places on the same web page
Disadvantages:
  • Despite the growing sophistication of search engines, many well thorough search phrases can still produce numerous lists of irrelevant web pages, which the user would still need to sift through to find what he/she was looking for
  • People that are not familiar with search engines may have difficulty using them, finding the information that they need, or even finding out which search engine was is best for what they are searching for
  • Majority of the search engines only search for keywords rather than searching for phrases

The Major Search Engines:

Google: this search engine provides both comprehensive coverage of the web along with great relevancy and continues be in the top rank as far as search engines go. Google offers users a wide range of features such as cached links that let you revive dead pages or see older versions of the recently changed ones. Users also have google_tv1.jpg access to dictionary definitions; integration of stock quotes street maps, not-a-query-yahoo.gif numbers and much more.
Yahoo: this search engine is the web’s oldest “directory”- a place where human editors can organize web sites into categories. Yahoo uses it’s own search technology, and provides users with excellent search results, and other specialized search options.

Yahoo focuses more on advertisers where as Google focuses more on the users; this is why Google is more popular, and more successful when it comes to providing users with better, and more relevant search results. Google supplies general information results, whereas Yahoo’s results are more consumer oriented, even if those results are not paid advertising for Yahoo. Google is associated with simplicity, usefulness, not to mention the pages that load fast; while, Yahoo is associated with rich interfaces, complex designs, and pages that load slowly.

Google carefully analyzes a web page’s text as well as where it links to, and manages to filter out a lot sites that have irrelevant content, or fake and broken links. If a website has too many links to different sites, Google will only include them at the top of the results list if they are relevant. For example, if a user is looking Puppies, and a certain website is called Puppies but has lots of links to cars, and apartments; Google won't list this site at the top or near the top of the results lists. Yahoo normally includes websites that are filled and almost overflowing with one particular word.

Top Five Favorite Search Engines:

Google: This is my favorite search engine, because it’s easy to use, and offers a wide variety of useful products and services.
Yahoo: This is also one of my favorites, although I hardly use it, as Google usually provides me with everything that I need.
Youtube: This is my favorite search engine for searching videos, and my favorite thing about YouTube is that it allows the user to upload personal videos and also provides a comfortable platform for users to interact.
Definitions.net: This is my favorite search engine for when I need to find the definition of a word. It’s easily accessible and very easy to use.
Synonyms.net: This is my favorite search engine when searching for synonyms because it’s easy to navigate and it’s also easily accessible.

We are lucky to have a wide range of general, meta and vertical/topical search engines; but it's important to know which ones to use, when to use them, and how to use them in order to discover which ones best fit our needs and wants, as well as save ourselves some time when conducting research.



References:

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